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Anna Röll
Follicle-Stimulating Hormone (FSH): Meaning, function, and normal values
What can a single hormone value reveal about fertility, the menstrual cycle, or menopause? Follicle-stimulating hormone (FSH) plays a key role in these processes and is often measured when hormonal changes are being evaluated. But what does this value actually indicate, and how should it be interpreted?
This article explains the functions of FSH in the body, outlines normal reference ranges, and clarifies what abnormal values may mean.
Table of Contents
What is FSH?
FSH stands for follicle-stimulating hormone. Hormones are chemical messengers that regulate numerous bodily functions—including growth, metabolism, and reproduction.
FSH belongs to the group of gonadotropins, meaning those hormones that control the function of the gonads: the ovaries in women and the testes in men. FSH is produced in the pituitary gland, a central hormonal control organ in the brain (NIH, 2025).
What functions does FSH fulfill in the body?
The effect of FSH differs depending on sex, life stage, and hormonal situation. While FSH levels are very low during childhood, they rise at the onset of puberty and contribute to sexual maturation.
Functions of FSH at a glance
| Sex | Life stage | Function |
|---|---|---|
| Women | Puberty to approx. 40–45 years | Promotion of egg cell maturation in the ovary; increase in FSH at the beginning of the menstrual cycle to stimulate follicle growth |
| Women | Menopause | Significant increase in FSH because the ovaries respond less to hormonal signals |
| Men | Puberty into later adulthood | Support of sperm production (spermatogenesis) in the testes |
| Men | With impaired fertility | FSH may be elevated when sperm production is reduced |
Source: Cleveland Clinic, 2023
Important:
FSH does not act in isolation but in interaction with other hormones such as luteinizing hormone (LH), estradiol, progesterone, and testosterone. Changes in a single hormone can affect the entire hormonal balance. Therefore, in medical diagnostics, FSH is usually evaluated as part of a more comprehensive hormone profile.
Which FSH values are considered normal?
The reference ranges for FSH depend on sex, age, and—in women—on the phase of the menstrual cycle.
| Group | Reference range (FSH) |
|---|---|
| Women, follicular phase | 2.5 – 10.2 IU/L |
| Women, ovulation phase | 3.4 – 33.4 IU/L |
| Women, luteal phase | 1.5 – 5.5 IU/L |
| Women, postmenopause | 26.7 – 133.4 IU/L |
| Men | 1.4 – 18.1 IU/L |
Source: DocCheck, 2025
Note:
Reference values may vary slightly depending on the laboratory. In addition, interpretation is only meaningful in connection with other laboratory values and the individual clinical situation.
What does an elevated FSH level mean?
An elevated FSH level may indicate that the ovaries or testes are no longer functioning properly. The body then attempts to compensate for this deficiency by releasing more FSH.
Possible causes in women:
-
Beginning or onset of menopause
-
Premature decline in ovarian function (premature ovarian insufficiency)
-
Irregular cycles or absence of menstruation (amenorrhea)
Possible causes in men:
-
Damage to the testes, e.g., due to infections or previous treatments such as chemotherapy
-
Impaired sperm production (impaired spermatogenesis)
Source: MedlinePlus, 2023, Mayo Clinic, 2024
What does a low FSH level mean?
A low FSH level often means that hormonal regulation in the brain is not functioning properly—specifically in the areas that regulate hormone production.
Possible causes:
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Disorders of the brain’s hormonal control centers (hypothalamus or pituitary gland)
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Stress, severe overweight, or undernutrition
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In women: hormonal disorders such as polycystic ovary syndrome (PCOS)
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Influence of medications, e.g., hormonal contraceptives or cortisone preparations (steroids)
Source: MedlinePlus, 2023
A single FSH value is often not sufficient—it should be evaluated in combination with other hormones (such as LH, estradiol, or testosterone).
FSH and pregnancy – how are they related?
FSH plays a central role in the development of a pregnancy because it enables egg maturation. If ovulation does not occur—for example, due to a too low or unusually high FSH level—fertility problems may arise. Especially in cases of an unfulfilled desire to have children, measuring the FSH level is therefore one of the first steps in hormonal evaluation.
What diagnostic significance does FSH have?
FSH is an important laboratory parameter for clarifying hormonal disorders:
-
In women: cycle disorders, unfulfilled desire to have children, assessment of menopausal status
-
In men: evaluation of fertility problems and hormonal disorders
Source: MedlinePlus, 2023
How can you test your FSH level?
The FSH level is usually determined through a blood test. In addition to testing at a doctor’s office, certified home tests—such as those from Homed-IQ—are now also available.
You take a small blood sample yourself (e.g., via a finger prick), which is then analyzed in a medical laboratory. Depending on the question, different test profiles may be useful—for example, in the context of fertility diagnostics, menopause, or a general hormone analysis.
Conclusion
Follicle-stimulating hormone (FSH) is a central indicator of hormonal balance and plays an important role in fertility as well as throughout the female cycle and menopause. Deviating values can provide indications of physical changes and help to specifically clarify possible causes.
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